Machine for manufacturing bags



Aug. 2, 1938. H. F. WATERS MACHINE FOR MANUFACTURING BAGS File d May 8, 1955 ATTORNEY.

Patented Aug. 2, 1938 UNITED STATES PATENT. OFFICE 2,125,158 Machine FOR MANUFACTURING mes Harry E. Waters, New York, N. Y. Application May 8, 1935, Serial No. 20,370

7 Claims.

, My present invention relates to improvements in the manufacture of bags and like containers and more particularly to an improved apparatus for making sift-proof, air-tight and liquid resist- 6 ant containers.

In the art of manufacturing bags and the like according to standard practices a web of material is first formed into a tube having overlapped edges and forming in the finished bag a longitudinal seam. To secure these overlapping edges together adhesive is supplied to one of the edges prior to the tube formation by means of a roll or other adhesive applying device. Thereafter the bag tube is cut off into the desired lengths and the bottom of the bag is then formed in a manner well known in the art. Either prior to or during the formation of the bottom, lines of adhesive are applied at the desired points so as to secure the various parts of the bottom in place. The bags, made according to standard practices, depend for their efficiency and successful performance as to sift-proofness on the ability of the manufacturer properly to apply the adhesive to the bag seams and bottom. Since various forms of material are used in making bags the effectiveness of the adhesive has been found to depend primarily upon the material from which the bag is made. bags made from kraft paper present no difficulties in satisfactorily securing the overlapped portions of the bag together. However, when waxed, paraffin or similar paper is used, the coating of the paperiprecludes. in many instances, the successful adhesion of the overlapped portions of the bag together. Particularly is this true when use 35 is made of rubber-like materials, as for example I that type of material known in the trade as ,pliofllm, or rubber coated or latex coated paper. It has heretofore been considered impossible satisfactorily to secure by ordinary adhesive means 40 the bag sections together. Thus in forming the longitudinal seam of the bag, it has been found that no real adhesion will take place so that when the bag is to be used for packaging sifting goods, such as powdered milk and the like, or when it is to be used as a package for liquids, such as oil, the seam will part thereby destroying any utility which the bag might have originally possessed.

Accordingly, a primary object of my present invention is to provide a new apparatus for the 5 manufacture of sift-proof, air-tight and liquidproof bags and like containers wherein the seams of the bag formed by overlapped edges of the material from which the bag is made are secured together by heat. Another object of my inven- 55 tion is to provide a new machine for forming bags and similar containers wherein when the material from which the bag is to be made is brought into tube form the overlapped edges are passed between heat sealing members which will form a substantially unbreakable longitudinal eam.

Another object of my provide a new apparatus bags wherein use. is made of waxed, greased, parafiinpapera-Pliofilm, rubber or rubber coated materials wherein two plies of material, after being brought into superimposed relation, are passed between heating rollers which will form longitudinal and transverse seal areas in the material. The material is then passed between cutoff rolls which sever the material through the sealed areas, thereby producing abag or container sealed along three edges and open at the remaining edge. A-feature of my invention resides in the provision of a heat sealing device for securing together overlapped edgesof material wherein the device comprises essentially two elements, one heat sealing element and the other a backing roll or member made of resilient material, as for example rubber. By the provision of such backing member, a perfect seal is insured in spite of variations in the manner in which the edges are overlapped due primarily to the fact that the resilient backing roll will exert a constant pressure on the overlapped area to force this area firmly against the heat applying roll.

' These and other objects of my present invention will become more apparent from a study of the following description taken in connection with the accompanying drawing in which like numerals refer to like parts throughout.

Referring to the drawing:

Fig. 1 diagrammatically illustrates my invention in use in a certain type of bag making machine;

Fig. 2 is a plan view thereof;

Fig. 3 is a further diagrammatic showing of the invention in use in a different type of bag making machine;

Fig. 4 is a plan view thereof;

Fig; '5 is a partial cross-sectional view on an enlarged scale of the form of Figs. 3 and 4;

Fig. 6 represents a slightly different type of bag which may be formed on the machine of Figs. 3 and 4;

Fig. '1 represents a slightly different type of bagwhich may be formed; and

\ Fig. 8 represents my invention in use in a bottoming device. 1

present invention is to for the manufacture of forming machine in l mented areas.

In Figs. 1 and 2 there is set forth the essential portions of a well known type of bag or envelope which a strip of material II and a strip of material ii are superimposed and passed between feed rolls it. Either strip may comprise fusible material or may comprise a sheet of base material coated with a fusible substance, or may be preprinted in defined areas with strips ll of fusible substance. A roll ll having 10 heated sealing projections I! thereon presses the combined webs against a backing roll II. If the entire adjacent surfaces of the webs are fusible it will be apparent that wherever the heated portions contact the webs there will be formed ce- If preprinted strips are in use the heating areas It must register with these strips. The backing roll I I is formed, in accordance with my invention, with a covering I! of yielding and heat-resisting rubber. I have discovered that a firm, absolute bond may best be obtained against a backing roll of this type as distinguished from the ordinary unyielding roll. The combined webs are then led between a cutting roll II and an anvil roll is, the blades on the cutting roll separating the webs into bags or envelopes Ill. It will be apparent that by placing the cuts within each fused or cemented area, each bag will be Joined along three edges. The open mouths of the'bags, while having fusible substance thereat, will not be sealed after currently herewith.

In Figs. 3, 4 and 5 there is schematically represented a type of bag-making machine wherein a material is formed into a continuous tube 3| by means of a heating roll 32 having a raised heating area 33 hearing against a backing be sealed together. The bags are separated, by a shearing roll 36 and an anvil roll 31, into bags 38. It is apparent that the separation may take place at the center 55 35, as illustrated in Fig. 7.

In Fig. 8 I have illustrated my-invention embodied in a bottomer of any well known type. In such abottomer an open-ended tubular blank in anywell known .4, or Fig. 6 may be i a rigid rodil surrounded by a rubber tube 54 I such as a piece of rubber steam-tubing". The

I surface of the rubber is preferably ribbed as at n in order that ribs will be formed in the sealed bottom, thereby strengthening the same. It will be noted that considerable pressure may be used pressure throughout the sealed area.

While I have specifically mentioned rubber as rigid bar having a covering of a heat-resistant, resilient substance having a ribbed surface.

3. In a device for adhering material together by the application of heat comprising in combination a heated element having a substantially throughout the area of the surfaces to be adhered to each other.

4. In a bag making machine, means to adhere overlapping against said heat sealing element.

5. In a bag making machine, means to adhere sealing element provided with a rubber covering capable of resisting high temperatures.

6. In a bag making machine, a former plate,

under uniform pressure.

-7. In a bag machine of the class described provided with a tube from a means to out said tube into predete ned lengths, means to close one end of each length of tube comprising 

